First Cuttings

Australian Plants Societies

Australian Plants online is brought to you by the 7 Societies that make up the Association of Societies for Growing Australian Plants (ASGAP).

Have you ever thought of joining one of the Societies? There is a Regional Society in every Australian state and also in the Australian Capital Territory. In addition, there are over 100 district groups established in centres throughout Australia.

The "Gumnuts" Newsletter

Gumnuts is an email newsletter on Australian native plants which is published 4-6 weekly. It covers a wide range of topics - limited only by the imagination of its subscribers.

To subscribe - please see the "Subscribe" section of the current issue.

You may unsubscribe at any time.

Beetle and moth put bite on problem weed

One of our "Gumnuts" correspondents recently found an article in the Northern Territory News about the use of a Mexican beetle (Malacorhinus irregularis) to help control the serious weed Mimosa pigra. The article reports that "The CSIRO announced yesterday that the beetle, which is relatively rare in its native Central America, had taken hold in the Top End with a devastating impact on the weed." The beetle attacks new seedlings and defoliates young immature plants.

Unfortunately the web link to the article no longer exists but there is a press release by the CSIRO on the release of another biological agent to control the same weed. This concerns the release of a the leaf feeding moth, Macaria palidata, also a native of Mexico.

"In its native range in Mexico, this moth is very common and damaging to Mimosa," says Dr Tim Heard, CSIRO Project leader. Free of its natural enemies, we predict that Macaria has the potential to be even more damaging in Australia," he says.

The larvae begin feeding by removing the top surface of young and mature leaves. If there are enough larvae they will completely defoliate the plant, thus reducing the plants growth rate, competitive ability and seed production.

Speaking in Darwin at the 3rd International Symposium on Management of Mimosa pigra, Dr Heard says the latest agent release highlights the excellent partnership between the Northern Territory Department of Infrastructure, Planning and Environment (DIPE). "Some agents establish and distribute themselves easily, others need helping along. What we've been able to do for this, and other agents, is to dovetail nicely with the department. CSIRO do the groundwork - the native range research, the host specificity testing in our quarantine facility and the initial release. The department will now commence mass rearing and distribution of the moths, without which the insect may not establish quickly, or perhaps not at all," says Dr Heard.

"We expect that (DIPE) will be able to rear and release about 1,000 moths per month. While we can't ever predict the fate of any biocontrol agent, we're confident that once we get the numbers, this moth will really do a lot of damage to Mimosa.

"This weed has the potential to invade many coastal tropical and sub-tropical areas in Australia," he says.

Biocontrol of Mimosa pigra is a joint Northern Territory Government (Department of Infrastructure, Planning & Environment)/CSIRO program. The research is supported by the Natural Heritage Trust.

If you've ever wondered why there are so many eucalypts growing in California (any why some Californians believe that they are native to that State), this excellent site is well worth a look. In fact, if you couldn't care less about eucalypts in California but are just interested in eucalypts per se, it's still worth a look. There's a host of information here, compiled by by Robert L. Santos of California State University.

It's not a pretty site - there are no photographs or diagrams - but it's a site no eucalypt-o-phile should ignore!

Here's a brief outline of the site.....

Section One - The Early Years: How and why eucalypts came to be so widely planted in California.

Section Two - Physical Properties and Uses: Information on identification, drought and frost resistance, suitable soils, timber strength and uses and other features.

Section Three - Problems, Care, Economics and Species

Notes

Bibliography

Looking underground for revegetation solutions

CSIRO Plant Industry is helping to 're-green' Australia by using soil bacteria to establish healthier native trees more quickly.

Dr Peter Thrall and his team have identified significant benefits associated with growing trees from seeds coated, or 'inoculated', with a peat-based substance containing specific strains of naturally occurring soil bacteria.

"When you look at a cleared agricultural landscape you can see there is often little or no natural vegetation left," Dr Thrall says.

"But what is not so obvious is that there is a huge diversity of soil organisms under the ground that may also be lost."

Many plants - including Australian natives such as acacias - grow in 'symbiotic' or mutually beneficial relationships with a range of soil organisms.

"In preliminary glasshouse and field trials we have found that Acacias inoculated with beneficial strains of a nitrogen-fixing bacteria called Bradyrhizobium survive better and grow faster than un-inoculated acacias," Dr Thrall says.

When the inoculated seed germinates and starts to grow, the bacteria form nodules on the plant's roots. These nodules take nitrogen from the air, which plants cannot use, and 'fix' it in the soil in a form they can use.

"It is this extra nitrogen, 'fixed' in the soil by the Acacias, that helps them grow better by effectively fertilising them," Dr Thrall says.

"Furthermore, we have found that other plants growing near to inoculated acacias, such as eucalypts, grow much better too."

But not all strains of Bradyrhizobium promote plant growth - some may have a negative effect. Also, different strains of Bradyrhizobium will have different effects depending on the species of Acacia they are associated with.

Dr Thrall and his team have been analysing soil samples collected from native remnant vegetation patches to see what types of bacteria are present and sort the helpful strains from the harmful ones.

As a result, several 'elite' strains of bacteria have been identified that have been used to inoculate a number of Acacia species for a large-scale field trial.

With Greening Australia Victoria's help, eight sites on different farms in the Bendigo region have been directly sown with Acacia seed inoculated with Bradyrhizobium to assess its effect on tree health and performance.

Each site has also been planted with a range of local native species to assess the effect on them too.

"Sowing native plant seed direct into the soil is a cost-effective and practical way of establishing trees," says Mr David Millsom, Greening Australia Victoria.

"If survival rates and vigour of direct seeded trees can be improved by inoculating tree seed with bacteria then this would be a huge help to landholders wanting to replant large areas of their properties to native vegetation."

"It is exciting to think that our knowledge of revegetation is extending beneath the soil surface to re-establish not only trees and other above-ground plants, but beneficial soil organisms too," Mr Millsom says.

According to Dr Thrall, the results from the trials will improve our understanding of the relationships between plants and bacteria.

"They will also help us to identify the best strains of bacteria to inoculate seed with," Dr Thrall says.

This project is a collaboration between CSIRO Plant Industry and Greening Australia Victoria with substantial on-ground support from the North Central Catchment Management Authority and the Department of Natural Resources and Environment, Victoria.

CSIRO Media Release

Encyclopaedia of Australian Plants - Volume 8 Published

The long awaited Volume 8 of Rodger Elliot and David Jones' monumental work is now on the book shelves. Covering Australian plant genera from "Pr to So", this latest work now only leaves one volume left to complete this huge task which started over 20 years ago (Volume 1 was published in 1981).

There will be a review of the book in the March 2003 issue of Australian Plants online but those who have earlier volumes will know exactly what to expect and will not be disappointed.

The UK's Natural History Museum in London has made available a native plant and wildlife database for all of the United Kindom, indexed conveniently by postal code! The aim is to encourage gardeners and other horticulturalists to plant the native trees, shrubs and flowers that are local to their areas. The Postcode Plants Database generates lists of native plants and wildlife for any specified postal district in the UK. Useful information is provided on what a native species is, encouraging people to plant native species, but not transplant them from nature.

This is an extremely useful resource and is a great model model for native plant databases elsewhere. It would be extremely useful if something similar to this could be developed for Australia.

Threatened Tasmanian eucalypts axed for suburban subdivision

WWF Australia has expressed concern at the recent clearing of hundreds of rare Eucalyptus risdonii trees during the development of ten residential blocks in the outer north-eastern outskirts of Hobart. The eucalypt species, also known as Risdon or silver peppermint, is listed as rare on the schedules of the Tasmanian Threatened Species Protection Act, and only occurs in the Clarence municipality in Hobart.

"This highlights the need for clear communication between councils and landholders with regard to threatened species represented on private land in their localities," said Dr Nicola Markus, WWF Australia Species Program Coordinator.

Dr Markus said the Threatened Species Network had obtained a copy of the subdivision permit issued by the Clarence City Council.

"It is disturbing that there are no conditions included in the permit in regard to threatened species, even though the Council appears to have known that E.risdonii was present," she said.

Peter McGlone, Tasmanian Co-ordinator, Threatened Species Network said he had visited the site at Tolpuddle Drive, Back Tea Tree and estimated that hundreds of E.risdonii trees had been cut down in preparation for fencing the boundaries of residential blocks.

Mr McGlone said he had been told that the clearing of the listed trees had occurred in early September. He said the Clarence City Council had issued a subdivision approval in February 2001, permitting the Tolpuddle Drive development.

"The Council's own vegetation map [contained in the report City of Clarence Natural Areas Inventory (1998)] clearly identifies E.risdonii as present across at least some of the land subject to this subdivision. Also, Council minutes refer to a public submission that stated concerns regarding destruction of rare and threatened native vegetation," he said.

The Threatened Species Network has written to the Clarence City Council seeking confirmation of the circumstances that led to the destruction of this threatened species.

"It is crucial to determine why the Council apparently did not inform the land owner of the presence of the species and, according to council records, apparently did not place conditions on the subdivision to protect it" said Dr Markus.

"Out of the ten blocks in this subdivision, five are covered entirely in E.risdonii and it wouldn't be possible to construct houses or drive ways without clearing hundreds more E.risdonii trees."

Waratah Paintings

Nikyla Amanda Smith is a traditional oil painting artist from the Sunshine Coast in Queensland. Nikyta specialises in painting waratahs and her work is truly exceptional. Take a look for yourself on her website.

"Australian Plants"....in print!

The Society's 48 page, colour (printed) journal, "Australian Plants" has been published quarterly since 1959. It carries articles of interest to both amateur growers and professionals in botany and horticulture. Its authors include the leading professional and amateur researchers working in with the Australian flora and many beautiful and high quality photographs of Australian plants are published in its pages. Topics covered by the journal cover a wide range and include landscaping, growing, botany, propagation and conservation.

A subscription to the print version of "Australian Plants" is $20 annually for 4 issues (overseas $AUS32) including postage. To subscribe, print out the Subscription Form and post or fax the appropriate fee to the address indicated on the form.

Note that the contents of "Australian Plants" and "Australian Plants online" are totally different.

These are some of the topics covered in recent issues of "Australian Plants":